Definitely the right star Barry, I'll need some clear sky to check anything more.
I've seen it jitter as well Dennis. I would have thought a platesolve and a sync would have put the mount on target though. I do have both maxim and thesky connected to the mount via poth. I'll have a play when it clears up.
I can still slew from 6188 in the south east to m27 in the north west, including a flip, and have m27 come up close to center on the sensor so it's not all bad
[edit]
My bad, I had 157 instead of 153 entered for E in the tak driver
